Slideshow: Road to 400G Ethernet

SANTA CLARA, Calif. – Engineers will gather in Victoria, British Columbia, next month to start defining a version of Ethernet capable of data rates up to 400 Gbits/second. The effort could take four years and faces a broad set of hurdles, outlined by the group’s acting chairman in a talk here.

Facebook and other large data-center operators called for terabit Ethernet as early as 2009 in the face of rising Web traffic. Engineers pushed back--arguing the technology is far too expensive--and are rallying around the 400G effort.

Products using serdes with individual lanes running at 25G are just now hitting the market and costs of bundling more than 16 lanes is prohibitive, said John D’Ambrosia, acting chair of the new 400G group. “It’s a question of doing it at the right cost so the cost per bit continues to fall,” he said.

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25G lanes are just getting started, while 10G lanes have been going strong for a decade.

Ethernet users are an increasingly broad collection of carriers, businesses and large data-center operators that want links of various distances and types to servers, racks and pods. “The landscape for what people are building is changing,” he said.

Given the wide set of options, the group initially will need to focus, addressing the most pressing needs first, D’Ambrosia said. “The reality is we will ultimately do all of it, not necessarily in this project, but we have to at least consider everything simultaneously so that we define something that’s flexible and can evolve,” he said.

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Historically, the most expensive products have used bundles of 16 fast lanes.

D’Ambrosia put out a broad call for participation. “You have to get involved--the decisions are not made by the IEEE, they are made at the IEEE by you,” he said.